Spectrophotometric determination of formaldehyde

A simple and very sensitive method for the determination of formaldehyde is described. Formaldehyde reacts with phloroglucinol in acid medium producing a yellow dye with λ(max) at 435nm. The method is useful for the determination of formaldehyde in the range 0-2.5μg in an overall volume of 10mL with molar absorptivity of 8.3 <x> 104 l mol-1 cm-1 and a relative standard deviation of 2% at 1.5μg level (n=10).